A mid-sized rosette species native to the Madrean sky islands — from Arizona, New Mexico, and west Texas into Chihuahua and Coahuila in northern Mexico — between roughly 1,200 and 2,500 m. Broad, short leaves in pale blue-grey to silvery green sit tightly together, edged and tipped with dark brown spines that draw a clean line around each blade. It is monocarpic: a plant typically takes 20 to 40 years to flower, then dies after fruiting. Cold hardiness is among the strongest in the genus, with reports of plants enduring close to −20°C in the wild. Treated as Agave parryi Engelm. by POWO (Kew) and followed here, the species spans several named subspecies and varieties that reflect its considerable variation across the range. The epithet honors Charles Christopher Parry, a 19th-century American plant explorer.
Native climate
Rainfall is spread fairly evenly across the year. Overall cool, at high elevation, with a wide temperature range, and cold winters.
A broad-scale picture of the native range. Real growing spots — rock crevices, fog belts — can be milder.
Sources: climate & elevation WorldClim 2.1 (1970–2000) · occurrences GBIF · native range POWO · current weather Open-Meteo
Care
Light & Placement
In habitat it grows on open, well-drained mountain slopes under intense high-elevation sun and steady, dry wind, so strong light and good airflow are essential. During the growing season, full sun outdoors keeps the rosette tight and brings out the silvery blue tones in the leaves. Japan's humid midsummer nights are harsher than its native climate, so a raised, breezy bench and light 20% shade help avoid scorch. Cold hardiness is high — open ground overwintering is feasible in much of central and southern Japan — though sheltering from prolonged winter rain on a bright eaves or window is the safer option.
Watering
In active growth, water thoroughly only once the substrate has fully dried, then let it dry again. Crown rot from prolonged wet and poor airflow is the main risk. In winter, hold back — once or twice a month is plenty.
Substrate
Drainage above all, in an inorganic mix. Small-grain Akadama : pumice : Kanuma = 4:3:3 is a reliable baseline. A taller pot improves wet-dry cycling; a mix that drains quickly from the crown area helps reduce the risk of crown rot.
Fertilizer & Supplements
A small amount of slow-release during active growth, plus a monthly liquid feed diluted to roughly half the label rate. Overfeeding loosens the rosette and dulls leaf color — restraint keeps the form tight.
Temperature & Overwintering
Optimal 18–32°C, with cold tolerance among the strongest in the genus — around −10°C is a workable floor. Open-ground overwintering is feasible across much of central and southern Japan, but combinations of prolonged rain with cold are best avoided by sheltering and keeping the substrate dry.
Starting from Seed
Where to source seeds
Pre-sowing treatment
Soak seeds for half a day in a fungicide solution (Benlate or Daconil) mixed with a plant tonic (Menedael or equivalent), each at label dilution. Seeds that remain floating are likely past their prime.
Substrate
Use a separate seedling mix that's fine-grained and near-sterile: fine Akadama, fine Kanuma, and vermiculite in equal 1:1:1 parts. Sterilize the mix with boiling water or a quick microwave pass before sowing.
Sowing method
Sow the flat, medium-sized seeds with no covering, or only the thinnest dusting of substrate. Space seeds at least 1 cm apart and arrange them so they don't clump together.
Light & temperature
Keep the tray in bright shade at a steady 25–30°C. Expect germination in 7–21 days. Germination depends strongly on seed freshness, but fresh seed tends to come up reasonably steady.
Watering
Bottom-water with the level 1–2 cm up the pot. For the first 2–3 weeks, prioritize keeping the medium moist, then drop the bottom-water level in steady stages as seedlings establish.
Fertilizer
No feeding right after germination. Once the true leaves emerge, give a heavily diluted liquid fertilizer once or twice a month — go lighter than the bottle suggests, as overfeeding leads to etiolation.
From Germination to Repotting
Germination through true leaves (first month)
Continue bottom watering in bright shade.
Weaning off bottom watering (months 1–2)
Lower the water level gradually, then switch to saucer watering.
First repotting (year 1–2)
Once roots reach the bottom of the pot, it's time.
Common Pitfalls
Crown rot
- Cause: prolonged rain, poor airflow, water pooling in the crown
- Prevention: shelter from open rain and water from the pot edge rather than over the rosette
Sunburn
- Cause: an abrupt move into direct sun causing tissue damage
- Prevention: ramp light up gradually over a week or two
Etiolation
- Cause: insufficient light
- Prevention: bring the LED closer right after germination, or move the seedlings to bright shade outdoors
Seeds fail to germinate
- Cause: old seeds, insufficient temperature
- Prevention: choose a trusted source, stabilize temperature with a heat mat
Notes
The leaf-tip spines are sharp and stiff.
